FIG. 18 is an oblique perspective view of a case member 100 of a cartridge. The case member 100 includes an upper half 103 and a lower half 104. Each of the upper half 103 and the lower half 104 has a thickness of about a half the thickness of the case member 100. They provide a medium storage section 102 for storing an information medium 101. The upper half 103 and the lower half 104 are welded with a method such as ultrasonic welding after the information medium 101 is placed in the medium storage section 102.
In general, each of the upper half 103 and the lower half 104 has a sliding surface 106 having a window section 105. The window section 105 has a generally U-shaped opening configured to allow a rotation driving means (not shown) and a head (not shown) to be inserted. The rotation driving means drives the rotation of the information medium 101. The head is used to send/receive user information for the information layer of the information medium 101.
The sliding surface 106 is depressed from the side surface 107 by about the thickness of the shutter member described below. The side surface 107 defines the thickness of cartridge including the upper half 103 and the lower half 104. The sliding surface 106 is a sliding surface on which a plate member of the shutter member for opening/closing the window section 105, and has a pair of open position determination sections 108 which defines an opening range of the shutter member.
When the cartridge includes a shutter member which slides only one side of the cartridge, it is possible that the sliding surface 106 has only one of the open position determination sections 108.
The case member 100 has a sliding sidewall 109 which is engaged with the sliding section of the shutter member such that the sliding section of the shutter member slides on the sliding side wall 109. The side wall 109 is located at the opening side of the window section 105 having the U-shaped opening.
The locking rib 110 coupled to a cutout of the sliding sidewall 109 restricts the separation of the sliding section of the shutter member from the case member 100.
The case member 100 has a shutter block section 111 which restricts the separation of the opposite edge of the sliding section of the shutter member away from the case member 100 in the direction of the thickness of the case member 100.
FIG. 19 is an oblique perspective view of the structure of the shutter member 200 which slides along the sliding sidewall 109 so as to open/close the window section 105.
The shutter member 200 includes a sliding section 201 which slides on the sliding sidewall 109 and plate sections 202 which opens/closes the window section 105. A shutter opener engaging section 203 is provided on an outer surface of the sliding section 201. The shutter opener engaging section 203 engages with a shutter opener (not shown) which slides on the shutter member 200 along the direction of sliding sidewall 109. Hook sections 204 and a guide protrusion section 205 are provided on an inner surface of the sliding section 201. Each of the hook section 204 has a hook which engages with the locking rib 110. The guide protrusion section 205 guides the sliding direction towards the sliding sidewall 109.
The edges 206 of the plate sections 202, which are located opposite side against the sliding section 201, engage with the shutter block section 111.
For example, when the shutter opener is provided on the sidewall of the case member, it is not necessary that the shutter opener engaging section 203 is provided on the outer surface of the sliding section 201.
Furthermore, the hook sections 204 are not essentially required so long as the shutter block section 111 and the opposite edges 206 are engaged with each other by some sort of hooking structure. In this case, the shutter member 200 would not detach from the case member 100.
Similarly, the guide protrusion section 205 is not essentially required, when the accuracy of the width of the sliding section 201 along a direction perpendicular to the sliding direction is sufficiently high and the accuracy of the width of the sliding surface 106 provided on the upper half 103 and the lower half 104 along the thickness direction of the case member is sufficiently high.
However, in general, the opposite edges 206 are processed to have a thin thickness in order to insert the opposite edges 206 underneath the shutter block sections 111. It is difficult to form a hook on the thin part. Furthermore, the accuracy of the widths described above are too high, the sliding property may be degraded. Therefore, in general, the hook sections 204 and the guide protrusion section 205 are provided on the inner surface of the sliding section 201.
In assembling a conventional cartridge having the structure above, the information medium 101 is stored in the medium storage section in the case member 100, the upper half 103 and the lower half 104 are fixed by means of welding and the like, the hook sections 204 and the locking rib 110 are engaged with each other by inserting the shutter member 200 from the sliding sidewall 109 of the case member 100, and then the opposite edges 206 are warped to engage with the shutter block sections 111. Thus, the assembly of the cartridge has been completed.
A method for producing the sliding section 201 and the plate sections 202 as a single unit, as its the shutter member 200 shown in FIG. 19, is disclosed in Reference 1, for example. In the method, three separate molds (i.e. a rigid mold, a flexible mold and a slide core) are used, the flexible mold and the slide core are separated from the rigid mold by injecting acetal resin and the like between the molds. Thus, the shutter member having a single piece integrating the sliding section and the plate sections can be obtained.
Reference 2 discloses a method for assembling the shutter member and the case member. In the method, a shutter part, including a sliding section, a plate section and a protrusion section which engages with a groove in the main surface of the case member, and another plate section are assembled onto the case member, and then the positioning protrusion section on the sliding section and the positioning depression section on the other plate section are engaged with each other, and then the melting protrusion section on the sliding section and the melting depression section on the other plate section are engaged as well as welded.
Reference 3 discloses a method for assembling the shutter member and the case member. In the method, the shutter member is divided at the substantially central portion of the thickness of the upper half and lower half of the case member, each of the divided portions of the shutter member has a sliding section, a plate section, and a protrusion section which engages with a groove in the main surface of the case member, the positioning protrusion section and depression section on the sliding section are engaged with each other onto the case member, and then the melting protrusion section and depression section on the sliding section are engaged as well as welded.
Furthermore, Reference 4 discloses a cartridge including a case member and a shutter member. The case member has a lower case, a stationary lid and a movable lid. The shutter member has a sliding section, a plate section provided on one side of the sliding section, and a non-rotatable plate section provided on the other side of the sliding section, and a rotatable plate section which engages with the non-rotatable plate section.
By rotating the rotatable plate section around the rotary shaft by 270 degrees while the hinge pin on the rotatable plate section and the C-shaped retainer on the lower case are engaged with each other, it is possible to take the information medium from the cartridge.
The sliding section and the plate section are fixed by engaging the L-shaped engaging depression section on the sliding section at the side of the lowercase with the L-shaped engaging projection section on the plate section for opening/closing the window section on the lower case, along the sliding direction of the sliding section.
The sliding section and the non-rotatable plate section are fixed by engaging the L-shaped engaging depression section of the sliding section at the side of the lid with the L-shaped engaging projection section on the non-rotatable plate section, along the sliding direction of the sliding section.
The non-rotatable plate section and the rotatable plate section are rotated around the ribs as the rotary shafts by engaging the hemispherical depression section on the rib of the non-rotatable plate section with the hemispherical protrusion section on the rib protruding from the rotatable plate section. The rotatable plate section is rotated around the rotary shaft of the shutter member in connection with the rotary shaft of the case member.
Reference 1: Japanese laid-open patent publication No. 3-259884 (page 3, right lower column, line 13 to page 4, left lower column, line 2, and FIGS. 4 and 5).
Reference 2: Japanese laid-open patent publication No. 11-3577 (Paragraph 0040 and FIG. 11)
Reference 3: Japanese aid-open patent publication No. 2000--285630 (Paragraphs 0023-0025 and FIG. 1)
Reference 4: Japanese National Phase PCT Laid-open Publication No. 2001-513935 (page 23, line 29 to page 25, line 1 and FIGS. 2-9)
The shutter member 200 includes a thin plate section 202 having a thickness of about 1 mm, and a sliding section 201 having a complicated shape which engages with the sliding sidewall 109 of the case member 100 such that the sliding section 201 slides on the sliding sidewall 109.
In the shutter member 200 having the plate section 202 and the sliding section 201 integrally molded using a method such as injection molding, there are problems such as the reduction of the planarity of the plate section 202 by the occurrence of local warps on the plate section 202, the difficulty in controlling the angle between the sliding section 201 and the plate section 202, which tends to be too sharp or too blunt, or the reduction of the parallelism of the surface of the plate section 202 against the sliding section 201 in the sliding direction, due to the internal stress caused by the temperature difference in the injection molded products and the mold-releasing force when the injection molded shutter member 200 is released from the mold. There is also a problem of low yield of the shutter member 200.
Even if the molding method described in Reference 1 is used, for example, there remains a problem of the difficulty in molding a shutter member precisely as designed, due to a persistent internal stress caused by the temperature difference, when the mold is released by moving the flexible mold and the slide core away from the rigid mold. Specifically, when the planarity of the plate section 202 is reduced, the warped portion of the plate section 202 produces gaps between the plate section and the side edges of the window section 105. This may cause the entry of dusts into the cartridge, or the loss of the function of the shutter member 200 by terminating the sliding motion of the shutter member 200 on the sliding surface 106 due to the edges of the plate 202 being in contact with the side edges of the window section 105.
Furthermore, the boundary surface between the sliding section and the plate section has an inconsistent thickness, and therefore, the significant temperature difference is caused on the boundary surface when the mold is released. Accordingly, even if the planarity of the plate section 202 is favorable, the angle between the sliding section 201 and the plate section 202 may be too sharp or too blunt. In this case, the following problem is frequently caused when the shutter member 200 is fitted onto the case member 100. Specifically, when the angle between the sliding section 201 and the plate section 202 is close to 90 degrees as shown in FIG. 20A, the plate section 202 becomes parallel to the sliding surface 106 when the shutter member is fitted onto the case member 100. In this case, the sliding motion is not prevented, since the plate section 202 is not in contact with the window section 105, for example. For this reason, the angle between the sliding section 201 and the plate section 202 is designed to be close to 90 degrees.
However, there may occur a case where the angle between the sliding section 201 and the plate section 202 is less than 90 degrees (i.e. sharp angle) as shown in FIG. 20B, or the angle between the sliding section 201 and the plate section 202 is greater than 90 degrees (i.e. blunt angle) as shown in FIG. 20C, due to the internal stress caused by the temperature difference in the shutter member 200 when the mold is released in the integral molding step described above.
When the shutter member 200 is fitted onto the case member 100 with the sharp angle between the sliding seotlon 201 and the plate section 202 as shown in FIG. 20B, the opposite edges 206 and/or vicinity of the opposite edges 206 is in contact with the sliding surface 106. This causes the difficulty in fitting the shutter member 200 onto the case member 100 and also causes scratches on the information layer of the information medium 101 due to the entry of the opposite edges 206 from the window section 105.
On the other hand, when the shutter member 200 is fitted onto the case member 100 with the blunt angle between the sliding section 201 and the plate section 202 as shown in FIG. 20C, there is no risk for providing any contact with the sliding surface 106 or providing any scratch on the information medium. However, due to the resistance against the force which attempts to shorten the distance of engagement between the shutter block section 111 and the opposite edges 206, there occurs problem that the opposite edges 205 come off of the shutter block section 111 when shutter member 200 slides, and/or, the pair of plate sections 202 fit the sliding surface 106 at the vicinity of sliding section 201 and at the vicinity of the shutter block section 111, but the plate section 202 is curved outward in the middle such that the plate section 202 does not cover the window section 105 as a flat surface.
Accordingly, when the angle between the sliding section 201 and the plate section 202 is significantly shifted from 90 degrees, it is necessary to correct the angle between the sliding section 201 and the plate section 202, before the shutter member 1 is fitted onto the case member 100. However, as described above, the thickness of the plate section 202 is about 1 mm. Therefore, the planarity of the plate section 202 may often be lost, or the plate section 202 and the sliding section 201 may often be broken at the joint portion, due to the forces applied to the plate section 202 in order to correct the angle between the sliding section 201 and the plate section 202. There is also a problem of low yield of the shutter member 200.
Furthermore, even if the angle between the sliding section 201 and the plate section 202 is corrected, immediately after the correction is made, the internal stress, once generated, causes revert this angle back to its original angle over time. Therefore, the correction of the angle between the sliding section 201 and the plate section 202 is not so reliable.
Additionally, in order to enhance the visibility for the users, of the various information such as the distinction between the information medium having the information layers on both sides and the information medium having the information layer on only one side, the distinction between the surface A and the surface B in the information medium having the information layers on both sides, and/or the capacity and the type of the information medium stored in the cartridge, a mat process (or embossed process) is performed on a surface of the plate section 202, which is opposite to the surface facing the sliding surface 106 so that a fine surface asperity is provided on the surface of the plate section 202. Thus, a printing process can be applied to the surface of the plate section 202.
This mat process can also improve the slidability against the sliding surface 106. By performing a mat process on the surface of the plate section 202, which faces the sliding surface 106, a shutter member having improved slidability can be obtained.
Furthermore, in order to fix the cartridge on a tray of the recording/reproduction device, the cartridge may be pressed so as to cause distortion in the cartridge. As a result, there is possibility that scratches are generated on the sliding surface 106. Performing an embossed process on a surface of the plate section 202, which faces the sliding surface 106, is effective to restrict such scratches to be generated on the sliding surface 106.
However, when the shutter member 200 is integrally molded, the fine asperity on the plate section 202 may causes the following problems. Specifically, when the slide core disclosed in Reference 1 is released, the fine asperity may restrict the mold to be released, for example. When the mold is forcefully released, breakage between the sliding section 201 and the plate section 202 may occur. When the slide core is pulled out, the fine asperity may be collapsed. For the reasons described above, when the shutter member 200 is integrally molded, it is impossible to perform the embossed process on the surface of the plate section 202, which faces the sliding surface 106. It is also impossible to improve the slidability between the shutter member 200 and the case member 100. It is further impossible to restrict scratches to be generated on the sliding surface 106.
References 2 and 3 are known as they provide means for solving the various problems which are inherent to the shutter member which is integrally molded.
References 2 and 3 relate to the shutter member precursor in which a plate section is integrally molded on only one side of the sliding section. The shutter member can be obtained by assembling the shutter member precursor onto the case member and by fusing the shutter member precursor. In this method, it is essential to apply heat and pressure to the shutter member precursor, when the shutter member precursor is fused.
The application of pressure during heating may cause distortion in the sliding section and the plate section. This distortion may change the angle between the sliding section and the plate section to a sharp angle or a blunt angle. Thus, a problem similar to the problem of Reference 1 described above may occur.
As described above, it is possible to correct the shape of the shutter member when the shutter member is integrally molded. However, in References 2 and 3, the shutter member precursor is assembled onto the case member, and then the shutter member precursor is fused. Further, in References 2 and 3, a guide groove which engages with a protrusion section on the shutter member is provided on the surface of the case member, on which the shutter member slides. It is impossible to make any correction after the shutter member precursor is fused.
This distortion may change the angle between the sliding section and the plate section as described above. In addition, in Reference 2, this distortion may reduce the parallelism between the plate section integrally molded with the sliding section and the plate section secured by welding, along the sliding direction of the sliding section. In addition, in Reference 3, this distortion may reduce the parallelism between the sliding directions of the sliding sections. As a result, it is difficult for the shutter member to properly slide along the sliding sidewall of the case member. When the parallelism is significantly shifted, the engagement of the shutter member with the shutter opener may become insufficient, or the engagement of the opposite edge with the shutter block section becomes insufficient, for example.
Reference 4 disclose a cartridge capable of taking the stored information medium from the cartridge, by rotating the movable lid fitted onto the lower case. The rotatable plate section of the shutter member is also rotated in relation to the rotation of the movable lid.
The sliding section and the plate section are fixed by engaging the L-shaped engaging depression section on the sliding section at the side of the lower case with the L-shaped engaging projection section on the plate section, with the application of force in the sliding direction of the sliding section. The sliding section and the non-rotatable plate section are fixed by engaging the L-shaped engaging depression section of the sliding section with the L-shaped engaging projection section on the non-rotatable plate section, with the application of force in the sliding direction of the sliding section. The processing accuracy of the L-shaped depression section and the L-shaped protrusion section is required.
For example, when the size of the L-shaped depression section is smaller than the size of the L-shaped protrusion section, or the size of the L-shaped protrusion section is larger than the size of the L-shaped depression section, the greater force is must be applied in order to engage the sliding section with the plate section (or the non-rotatable plate section). However, the direction to which the force is applied is the sliding direction of the sliding section, and therefore, the sliding section slides when the force is applied. For this reason, it is difficult to apply the force, and it is possible to break the portion in which the L-shaped depression section and the L-shaped protrusion section are engaged with each other.
On the other hand, when the size of the L-shaped depression section is larger than the size of the L-shaped protrusion section, or the size of the L-shaped protrusion section is smaller than the size of the L-shaped depression section, the shutter member may easily disassembled at the engagement portion. This may lead to the lack of reliability of cartridge in the recording/reproduction device, for example.
Furthermore, the non-rotatable plate section and the rotatable plate section are engaged by rotatabley engaging hemispherical depression section and hemispherical protrusion section. For this reason, the engagement strength of the engagement portion may be reduced by the external force applied to the shutter member when the sliding motion of the shutter member its repeated, and the shutter member may easily disassembled at the engagement portion.
The present invention has been made in view of the problems described above. One purpose of the present invention is to provide a cartridge and a shutter member used in the cartridge which has high parallelism between the plate member and the sliding surface of the case member and which does not provide any resistance in opening/closing the window section on the sliding surface.